Window Data

(I know this has been discussed before, but a quick search doesn't find it. Forgive the repetition.)

I have here LBNL Window 5a output describing the optical properties of a glazing system. Can I use this with Radiance & if so, how? Are there any docs which I can read?

···

--
Randolph M. Fritz • [email protected]
Environmental Energy Technologies Division • Lawrence Berkeley Labs

I have here LBNL Window 5a output describing the optical properties of a
glazing system. Can I use this with Radiance & if so, how? Are there any
docs which I can read?

Err... isn't it Optics in the LBNL toolchain outputting the optical properties of glazing? That one is supported by a special preprocessing tool "optics2rad". From the manpage:

optics2rad converts Optics 5 output to correct Radiance input.

Does this help?

Cheers, Lars.

I have here LBNL Window 5a output describing the optical properties of a
glazing system. Can I use this with Radiance & if so, how? Are there any
docs which I can read?

Err... isn't it Optics in the LBNL toolchain outputting the optical properties of glazing? That one is supported by a special preprocessing tool "optics2rad".

Oh. Yes, you're right.

Does this help?

Yes, thanks!

So--different problem. This is what I'm looking at:

Optical Properties for Glazing System

Angle 0 10 20 30 40 50 60 70 80 90 Hemis

Vtc : 0.620 0.624 0.615 0.604 0.590 0.560 0.493 0.364 0.175 0.000 0.521

Rf : 0.300 0.294 0.292 0.294 0.304 0.323 0.360 0.444 0.628 0.999 0.344

Rb : 0.256 0.250 0.249 0.253 0.264 0.287 0.338 0.456 0.684 1.000 0.319

Tsol : 0.376 0.378 0.373 0.366 0.357 0.339 0.300 0.223 0.108 0.000 0.316

Rf : 0.454 0.449 0.448 0.449 0.457 0.470 0.495 0.556 0.699 0.999 0.483

Rb : 0.438 0.435 0.433 0.433 0.438 0.450 0.479 0.552 0.705 1.000 0.469

Abs1 : 0.153 0.155 0.161 0.166 0.168 0.172 0.186 0.204 0.179 0.001 0.173

Abs2 : 0.018 0.018 0.018 0.018 0.019 0.019 0.019 0.017 0.013 0.000 0.018

SHGCc: 0.402 0.405 0.400 0.394 0.385 0.368 0.330 0.253 0.134 0.000 0.344

Tdw-K : 0.300

Tdw-ISO: 0.453

Tuv : 0.229

This looks like BRTDF data, maybe, and I suspect it can be used. Any pointers appreciated!

···

On 2010-09-02 11:06:13 -0700, Lars O. Grobe said:

--
Randolph

Hi Randolph,

My guess is you're looking at angular transmittance and reflectance data. This can be used, but would need to be translated into a brightdata modifier on a trans material. There is no program to do this for you, but the translation is not particularly difficult if you only care about transmission. I'm guessing that "Vtc" is visible transmittance, which you could put into a Radiance .dat file with an appropriate header:

# Visible transmittance data from Window 5a
1
0 90 10
0.620 0.624 0.615 0.604 0.590 0.560 0.493 0.364 0.175 0.000

Your scene file would then reference this data. Let's assume you put it into a data file called "glazing1.dat":

void brightdata glazing1_angT
4 noop glazing1.dat . acos(Rdot)/DEGREE
0
0

glazing1_angT trans glazing1_trans
0
0
7 1 1 1 0 0 1 1

···

-------
The above material will have zero reflectance, whereas you seem to have quite a bit of reflection from this glazing. I am confused by the duplicate Rf and Rb lines, so I don't know what to do with them. You probably need to employ the BRTDfunc material to handle this properly, converting the data into functions using tabfunc. That would take a little more time and thought, and I'm not sure it's worth the effort given the other unknowns.

-Greg

From: "Randolph M. Fritz" <[email protected]>
Date: September 2, 2010 11:41:23 AM PDT

On 2010-09-02 11:06:13 -0700, Lars O. Grobe said:

I have here LBNL Window 5a output describing the optical properties of a
glazing system. Can I use this with Radiance & if so, how? Are there any
docs which I can read?

Err... isn't it Optics in the LBNL toolchain outputting the optical properties of glazing? That one is supported by a special preprocessing tool "optics2rad".

Oh. Yes, you're right.

Does this help?

Yes, thanks!

So--different problem. This is what I'm looking at:

Optical Properties for Glazing System
Angle 0 10 20 30 40 50 60 70 80 90 Hemis
Vtc : 0.620 0.624 0.615 0.604 0.590 0.560 0.493 0.364 0.175 0.000 0.521
Rf : 0.300 0.294 0.292 0.294 0.304 0.323 0.360 0.444 0.628 0.999 0.344
Rb : 0.256 0.250 0.249 0.253 0.264 0.287 0.338 0.456 0.684 1.000 0.319
Tsol : 0.376 0.378 0.373 0.366 0.357 0.339 0.300 0.223 0.108 0.000 0.316
Rf : 0.454 0.449 0.448 0.449 0.457 0.470 0.495 0.556 0.699 0.999 0.483
Rb : 0.438 0.435 0.433 0.433 0.438 0.450 0.479 0.552 0.705 1.000 0.469
Abs1 : 0.153 0.155 0.161 0.166 0.168 0.172 0.186 0.204 0.179 0.001 0.173
Abs2 : 0.018 0.018 0.018 0.018 0.019 0.019 0.019 0.017 0.013 0.000 0.018
SHGCc: 0.402 0.405 0.400 0.394 0.385 0.368 0.330 0.253 0.134 0.000 0.344
Tdw-K : 0.300
Tdw-ISO: 0.453
Tuv : 0.229

This looks like BRTDF data, maybe, and I suspect it can be used. Any pointers appreciated!

--
Randolph

Hi Randolph

the duplicate Rf Rb values are for solar properties. The first three lines are visual (or light), the next three are solar, the following two are the (solar) absorption in pane 1 and pane 2.

I seem to remember that Optics has an export function "radiance input data". Below is an old "recipe" what to do with the data ... it is not really verified, though.

Best
Achim

Advanced Glazing
The default material “glass” has its limitations in regard to reproduction of optical properties of modern selective glass products. A different approach is recommended.
In LBNL Optics, chose the coated glass of interest and export this to “Radiance Format” (file export)
The resulting file has entries of the type
void BRTDfunc YME0185_6_front
10
       0.044 0.053 0.060
       0.817 0.852 0.839
       0 0 0
       .
0
9 0 0 0 0 0 0 0 0 0

void BRTDfunc YME0185_6_back
10
       0.037 0.043 0.042
       0.817 0.852 0.839
       0 0 0

where the first triplets are RGB reflectance values. In the header part of the file, the location of the coating (front or back) can be found – in this example, the back side is coated.
Now open the Perl script “glaze” (in /opt/rad/bin or wherever Radiance resides on the computer) and edit / add an entry for the coated glass in the lines
set sn_arr=("clear glass" "VE1-2M low-E coating" "PVB laminated" "V-175 white frit" "V-933 warm gray frit" "SYP YME0185" "SYP YDE01-2M" "SYP YRE0146")
# Glass-side hemispherical reflectances for each surface type:
set rg_r_arr=(0.074 0.065 .11 0.33 0.15 0.044 0.053 0.291)
set rg_g_arr=(0.077 0.058 .11 0.33 0.15 0.053 0.050 0.320)
set rg_b_arr=(0.079 0.067 .11 0.33 0.15 0.060 0.051 0.371)
# Coating-side hemispherical reflectance for each surface type:
set rc_r_arr=(0.074 0.042 .11 0.59 0.21 0.037 0.055 0.087)
set rc_g_arr=(0.077 0.049 .11 0.59 0.21 0.043 0.048 0.057)
set rc_b_arr=(0.079 0.043 .11 0.59 0.21 0.042 0.056 0.135)
# Hemispherical (normal) transmittance for each surface type:
set tn_r_arr=(0.862 0.756 0.63 0.21 0.09 0.817 0.734 0.419)
set tn_g_arr=(0.890 0.808 0.63 0.21 0.09 0.852 0.786 0.480)
set tn_b_arr=(0.886 0.744 0.63 0.21 0.09 0.839 0.717 0.458)
# Boolean whether coatings can have partial coverage:
set part_arr=(0 0 0 1 1 0 0 0)

Now run the “glaze” script and follow instructions. The output is a detailed glass description which should be copied into the “Material.mat” file of the Radiance model.

···

On Sep 2, 2010, at 9:06 PM, Greg Ward wrote:

Hi Randolph,

My guess is you're looking at angular transmittance and reflectance data. This can be used, but would need to be translated into a brightdata modifier on a trans material. There is no program to do this for you, but the translation is not particularly difficult if you only care about transmission. I'm guessing that "Vtc" is visible transmittance, which you could put into a Radiance .dat file with an appropriate header:

# Visible transmittance data from Window 5a
1
0 90 10
0.620 0.624 0.615 0.604 0.590 0.560 0.493 0.364 0.175 0.000

Your scene file would then reference this data. Let's assume you put it into a data file called "glazing1.dat":

void brightdata glazing1_angT
4 noop glazing1.dat . acos(Rdot)/DEGREE
0

glazing1_angT trans glazing1_trans
0
7 1 1 1 0 0 1 1

-------
The above material will have zero reflectance, whereas you seem to have quite a bit of reflection from this glazing. I am confused by the duplicate Rf and Rb lines, so I don't know what to do with them. You probably need to employ the BRTDfunc material to handle this properly, converting the data into functions using tabfunc. That would take a little more time and thought, and I'm not sure it's worth the effort given the other unknowns.

-Greg

From: "Randolph M. Fritz" <[email protected]>
Date: September 2, 2010 11:41:23 AM PDT

On 2010-09-02 11:06:13 -0700, Lars O. Grobe said:

I have here LBNL Window 5a output describing the optical properties of a
glazing system. Can I use this with Radiance & if so, how? Are there any
docs which I can read?

Err... isn't it Optics in the LBNL toolchain outputting the optical properties of glazing? That one is supported by a special preprocessing tool "optics2rad".

Oh. Yes, you're right.

Does this help?

Yes, thanks!

So--different problem. This is what I'm looking at:

Optical Properties for Glazing System
Angle 0 10 20 30 40 50 60 70 80 90 Hemis
Vtc : 0.620 0.624 0.615 0.604 0.590 0.560 0.493 0.364 0.175 0.000 0.521
Rf : 0.300 0.294 0.292 0.294 0.304 0.323 0.360 0.444 0.628 0.999 0.344
Rb : 0.256 0.250 0.249 0.253 0.264 0.287 0.338 0.456 0.684 1.000 0.319
Tsol : 0.376 0.378 0.373 0.366 0.357 0.339 0.300 0.223 0.108 0.000 0.316
Rf : 0.454 0.449 0.448 0.449 0.457 0.470 0.495 0.556 0.699 0.999 0.483
Rb : 0.438 0.435 0.433 0.433 0.438 0.450 0.479 0.552 0.705 1.000 0.469
Abs1 : 0.153 0.155 0.161 0.166 0.168 0.172 0.186 0.204 0.179 0.001 0.173
Abs2 : 0.018 0.018 0.018 0.018 0.019 0.019 0.019 0.017 0.013 0.000 0.018
SHGCc: 0.402 0.405 0.400 0.394 0.385 0.368 0.330 0.253 0.134 0.000 0.344
Tdw-K : 0.300
Tdw-ISO: 0.453
Tuv : 0.229

This looks like BRTDF data, maybe, and I suspect it can be used. Any pointers appreciated!

--
Randolph

_______________________________________________
Radiance-general mailing list
[email protected]
http://www.radiance-online.org/mailman/listinfo/radiance-general

[email protected]

It looks to me like the file that Randolph has generated is from the WINDOW
5 program not Optics.

Optics5 does generate the file that Achim refers to below.

Robin Mitchell

Windows & Daylighting Group

Lawrence Berkeley National Laboratory

···

From: [email protected]
[mailto:[email protected]] On Behalf Of Achim
Geissler
Sent: Thursday, September 02, 2010 12:41 PM
To: Radiance general discussion
Subject: Re: [Radiance-general] Re: Window Data

Hi Randolph

the duplicate Rf Rb values are for solar properties. The first three lines
are visual (or light), the next three are solar, the following two are the
(solar) absorption in pane 1 and pane 2.

I seem to remember that Optics has an export function "radiance input data".
Below is an old "recipe" what to do with the data ... it is not really
verified, though.

Best

Achim

Advanced Glazing

The default material "glass" has its limitations in regard to reproduction
of optical properties of modern selective glass products. A different
approach is recommended.

* In LBNL Optics, chose the coated glass of interest and export this
to "Radiance Format" (file export)
* The resulting file has entries of the type

void BRTDfunc YME0185_6_front

10

      0.044 0.053 0.060

      0.817 0.852 0.839

      0 0 0

      .

0

9 0 0 0 0 0 0 0 0 0

void BRTDfunc YME0185_6_back

10

      0.037 0.043 0.042

      0.817 0.852 0.839

      0 0 0

where the first triplets are RGB reflectance values. In the header part of
the file, the location of the coating (front or back) can be found - in this
example, the back side is coated.

* Now open the Perl script "glaze" (in /opt/rad/bin or wherever
Radiance resides on the computer) and edit / add an entry for the coated
glass in the lines

set sn_arr=("clear glass" "VE1-2M low-E coating" "PVB laminated" "V-175
white frit" "V-933 warm gray frit" "SYP YME0185" "SYP YDE01-2M" "SYP
YRE0146")

# Glass-side hemispherical reflectances for each surface type:

set rg_r_arr=(0.074 0.065 .11 0.33 0.15 0.044 0.053 0.291)

set rg_g_arr=(0.077 0.058 .11 0.33 0.15 0.053 0.050 0.320)

set rg_b_arr=(0.079 0.067 .11 0.33 0.15 0.060 0.051 0.371)

# Coating-side hemispherical reflectance for each surface type:

set rc_r_arr=(0.074 0.042 .11 0.59 0.21 0.037 0.055 0.087)

set rc_g_arr=(0.077 0.049 .11 0.59 0.21 0.043 0.048 0.057)

set rc_b_arr=(0.079 0.043 .11 0.59 0.21 0.042 0.056 0.135)

# Hemispherical (normal) transmittance for each surface type:

set tn_r_arr=(0.862 0.756 0.63 0.21 0.09 0.817 0.734 0.419)

set tn_g_arr=(0.890 0.808 0.63 0.21 0.09 0.852 0.786 0.480)

set tn_b_arr=(0.886 0.744 0.63 0.21 0.09 0.839 0.717 0.458)

# Boolean whether coatings can have partial coverage:

set part_arr=(0 0 0 1 1 0 0 0)

* Now run the "glaze" script and follow instructions. The output is a
detailed glass description which should be copied into the "Material.mat"
file of the Radiance model.

On Sep 2, 2010, at 9:06 PM, Greg Ward wrote:

Hi Randolph,

My guess is you're looking at angular transmittance and reflectance data.
This can be used, but would need to be translated into a brightdata modifier
on a trans material. There is no program to do this for you, but the
translation is not particularly difficult if you only care about
transmission. I'm guessing that "Vtc" is visible transmittance, which you
could put into a Radiance .dat file with an appropriate header:

# Visible transmittance data from Window 5a
1
0 90 10
0.620 0.624 0.615 0.604 0.590 0.560 0.493 0.364 0.175 0.000

Your scene file would then reference this data. Let's assume you put it
into a data file called "glazing1.dat":

void brightdata glazing1_angT
4 noop glazing1.dat . acos(Rdot)/DEGREE
0
0

glazing1_angT trans glazing1_trans
0
0
7 1 1 1 0 0 1 1

-------
The above material will have zero reflectance, whereas you seem to have
quite a bit of reflection from this glazing. I am confused by the duplicate
Rf and Rb lines, so I don't know what to do with them. You probably need to
employ the BRTDfunc material to handle this properly, converting the data
into functions using tabfunc. That would take a little more time and
thought, and I'm not sure it's worth the effort given the other unknowns.

-Greg

From: "Randolph M. Fritz" <[email protected]>

Date: September 2, 2010 11:41:23 AM PDT

On 2010-09-02 11:06:13 -0700, Lars O. Grobe said:

I have here LBNL Window 5a output describing the optical properties of a

glazing system. Can I use this with Radiance & if so, how? Are there any

docs which I can read?

Err... isn't it Optics in the LBNL toolchain outputting the optical
properties of glazing? That one is supported by a special preprocessing tool
"optics2rad".

Oh. Yes, you're right.

Does this help?

Yes, thanks!

So--different problem. This is what I'm looking at:

Optical Properties for Glazing System

Angle 0 10 20 30 40 50 60 70 80 90 Hemis

Vtc : 0.620 0.624 0.615 0.604 0.590 0.560 0.493 0.364 0.175 0.000 0.521

Rf : 0.300 0.294 0.292 0.294 0.304 0.323 0.360 0.444 0.628 0.999 0.344

Rb : 0.256 0.250 0.249 0.253 0.264 0.287 0.338 0.456 0.684 1.000 0.319

Tsol : 0.376 0.378 0.373 0.366 0.357 0.339 0.300 0.223 0.108 0.000 0.316

Rf : 0.454 0.449 0.448 0.449 0.457 0.470 0.495 0.556 0.699 0.999 0.483

Rb : 0.438 0.435 0.433 0.433 0.438 0.450 0.479 0.552 0.705 1.000 0.469

Abs1 : 0.153 0.155 0.161 0.166 0.168 0.172 0.186 0.204 0.179 0.001 0.173

Abs2 : 0.018 0.018 0.018 0.018 0.019 0.019 0.019 0.017 0.013 0.000 0.018

SHGCc: 0.402 0.405 0.400 0.394 0.385 0.368 0.330 0.253 0.134 0.000 0.344

Tdw-K : 0.300

Tdw-ISO: 0.453

Tuv : 0.229

This looks like BRTDF data, maybe, and I suspect it can be used. Any
pointers appreciated!

--

Randolph

_______________________________________________
Radiance-general mailing list
[email protected]
http://www.radiance-online.org/mailman/listinfo/radiance-general

[email protected]

Thank you all.

BTW, I did not generate the file; this is what I have been handed for data on these windows.

Someday soon I'll have an MS-Windows system to run LBL-Windows on.

···

--
Randolph

What I settled for as a first try was a simple "trans" material. If that produces sufficiently accurate results, I'm not going to do any more work.

# Very approximate glazing model--may need improvement

# Optical Properties for Glazing System (xxx)

···

#
# Angle 0 10 20 30 40 50 60 70 80 90 Hemis
#
# Vtc : 0.620 0.624 0.615 0.604 0.590 0.560 0.493 0.364 0.175 0.000 0.521
# Rf : 0.300 0.294 0.292 0.294 0.304 0.323 0.360 0.444 0.628 0.999 0.344
# Rb : 0.256 0.250 0.249 0.253 0.264 0.287 0.338 0.456 0.684 1.000 0.319
#

# As a first approximation, the hemispherical transmittance, 0.521, is
# used, and the average of the outside and inside hemispherical
# reflectances (0.344 and 0.319 = 0.332) is used.
#
# For details of the calculation which gave rise to those numbers, see
# Finlayson, E. U, D. K Arasteh, C. Huizenga, M. D Rubin, and M. S
# Reilly. WINDOW 4.0: Documentation of calculation
# procedures. Berkeley, CA: Lawrence Berkeley Laboratory, July 1,
# 1993.
# http://www.osti.gov/bridge/product.biblio.jsp?query_id=1&page=0&osti_id=10112503.

void

trans glazing
0
7 1 1 1 0 0.332 0.521 1

--
Randolph